Alwin HardenbolSwedish University of Agricultural Sciences | SLU · Department of Ecology
Ph.D. in Ecology
Doing a PostDoc combining forest ecology with remote sensing
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Citations since 2017
10 Research Items
Ecologist with a strong interest in conservation biology research and particularly on anthropogenic effects on biodiversity. Knowledgeable in many different subfields of ecology and in the application of remote sensing techniques for ecology. Fascinated by all taxonomic groups, but most experienced with birds, mammals, and plants. Advancing practical nature conservation efforts and better understanding human impacts are at the heart of my motivation.
January 2017 - December 2020
- PhD Student
- Dynamics of biodiversity-rich deciduous trees and microhabitats in boreal forests
July 2015 - January 2016
- Master's Student
- Research on the behavioural and ecological response of conspecific bank voles to anti-stress pheromones after a predatory attempt by a least weasel.
September 2014 - April 2016
Field of study
- Biology with a specialisation in Conservation and Systems Ecology
September 2010 - July 2014
Field of study
- Biology with a double major in Ecology and Evolution, and Marine Ecology; Minor in Arctic and Antarctic Studies
1. In a landscape consisting primarily of intensive forestry interspersed with some protected areas, multifunctional forestry with retention trees can play a crucial role in nature conservation. Accurate mapping of retention trees is important for guiding landscape-level conservation and forest management and improving landscape connectivity. Sizea...
Current remote sensing methods can provide detailed tree species classification in boreal forests. However, classification studies have so far focused on the dominant tree species, with few studies on less frequent but ecologically important species. We aimed to separate European aspen (Populus tremula L.), a biodiversity-supporting tree species, f...
Establishing protected areas and maintaining biodiversity in managed forests are the main methods to conserve forest habitats and their biodiversity. The habitat characteristics that affect forest biodiversity in both protected and managed forests occur on different spatial scales, with the smallest scale consisting of structures at the level of si...
Silvicultural practices, effective fire suppression, and increased browser densities have profoundly altered structural diversity in boreal forests. Prescribed burning and retention forestry may counteract losses in structural diversity in managed forests, by maintaining higher deciduous admixture. We constructed an experiment on 18 sites with thre...
The conservation of habitats and ecosystems is widely regarded as the most efficient way to maintain biodiversity. Protected areas are, however, under the continuous influence of natural dynamics that may affect their structure and functioning. In boreal forests, succession in protected forests may change their ecological properties, including tree...
Tree cavities are microhabitats used by multiple taxa and are considered indicators of forest biodiversity. The factors that affect cavity occurrence and its dynamics are poorly known. We studied tree-and stand-level factors that affect cavity persistence in boreal forests. Cavities of Eurasian Three-toed Woodpeckers (Picoides tridactylus) (n = 654...
Tree cavities are microhabitats used by multiple taxa, and are considered indicators of forest biodiversity. The factors that affect cavity occurrence and dynamics are poorly known. Trying to answer this, we explored tree- and stand-level factors that affect cavity persistence under boreal conditions. Using a 31-year annual survey of newly made cav...
Abstract Predation involves more than just predators consuming prey. Indirect effects, such as fear responses caused by predator presence, can have consequences for prey life history. Laboratory experiments have shown that some rodents can recognize fear in conspecifics via alarm pheromones. Individuals exposed to alarm pheromones can exhibit behav...
I am analysing data of woodpecker-made holes and I am interested in seeing what covariates and to what degree affect the survival of these holes (otherwise known as cavities). However, I encounter the complication that quite many trees contain multiple holes and thus, if the tree falls (which is the most common cause of a cavity death) it takes all these cavities in that tree down. Therefore, I wanted to have the tree's identity number as a random effect in my model. Thus I added frailty(tree_id) to my R script in the coxph function.
Another type of correction that I applied for more than one cavity in a single tree was to only keep 1 cavity and give it the median "age" value of all these cavities that were present in the particular single tree. The covariates that I test for do not change per cavity, but rather per tree.
Which approach is correct, if any?
Thank you very much for your help in advance!
Most tree cavities in boreal forests are made by woodpeckers, but there is quite limited knowledge about the numbers, survival, and reuse of this dynamic microhabitat in various types of forests. In this project the ecology and importance of woodpecker-made cavities are studied with large and long-term data sets from southern Finland. The time scale of the study covers over three decades with information of the nest tree characteristics, and with full lifespan monitoring focusing on the survival and reuse of hundreds of cavities of several boreal woodpecker species. The project is carried out in collaboration with the University of Helsinki, the University of Eastern Finland, and the Natural Resources Research Institute Finland.
The three-toed woodpecker Picoides tridactylus is a key indicator species of bird and structural diversity in forest environments. In this project we study various aspects of its ecology based both on long-term and exceptionally large data sets from southern Finland. The study topics include population biology, nesting ecology and nest trees, foraging ecology and genetics of the three-toed woodpecker. Also spatial ecology of the species in dynamic forest landscapes is investigated. The project is carried out in collaboration with the University of Helsinki, the University of Eastern Finland, and the Natural Resources Research Institute Finland.
My research aims to, first and foremost, provide solid scientific evidence of the assumed current decline of European aspen in nature reserves. A very urgent project according to prior research as aspen may disappear from old-growth boreal forests in a short period of time without intervention. Moreover, I will study the impacts which this decline of aspen could have on cavity-nesting bird species which are strongly associated with aspen for nesting purposes. Current questions that I will try to answer are: 1) Is aspen declining in nature reserves? This is assumed to occur due to the combined effects of a lack of large-scale disturbances and heavy browsing from moose (Alces alces). 2) Is the occurrence of aspen in nature reserves correlated to the occurrence of associated cavity-nesting birds? Aspen is the most important cavity tree in the Western Palearctic for cavity-nesting bird species. 3) Does the amount of aspen in surrounding managed forests influence the abundance of cavity-nesting birds within protected sites? Our aim is to eventually provide management solutions in order to conserve aspen in nature reserves.